US4646240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for determining geological facies
Assignee: Schlumberger Technology Corp
•
Filing: 1986-04-07
•
Granted: 1987-02-24
•
Expires: 2006-04-07
Abstract
Abstract In a method and apparatus for obtaining a recording of facies of geological formations, logging instruments are moved in a borehole to produce log measurements at successive levels of the borehole. With each level is associated a reference sample whose coordinates are constituted by the respective measurements in a multidimensional space defined by the different logs. The scatter of samples thus obtained is analyzed to distinguish modes characteristic of clusters in which the concentration of samples is the highest. The samples may then be associated with selected modes to form classes each characteristic of a respective facie, and the facies then displayed as a function of the depth of the respective associated sample.
Inventors
- 👤 Oberto Serra
- 👤 Hayden Abbott
- 👤 Yves Kerbart
- 👤 Philippe Vincent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:28
CPC Classifications
G; G01; G01V; G01V11/00; G01V11/002; Y; Y10; Y10S; Y10S706/00; Y10S706/902; Y10S706/928; Y10S706/929
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
204 words
A method of predicting the facies of a geological formation traversed by a borehole comprising: (a) moving a sonde through a plurality of predetermined levels in a borehole traversing a geological formation and recording the log measurements taken by the sonde at each of the predetermined levels; (b) selecting the recorded log measurements which are stable over consecutive levels; (c) assigning the selected log measurements to points in an n dimensional space in which n is equal to the number of log measurements recorded at each of the levels; (d) selecting pairs of modes which are furthest apart from each other in the n dimensional space, each of the modes corresponding to a point of maximum density of the points in the n dimensional space; (e) assigning each point in the n dimensional space to the respective closest mode, thereby defining classes of log measurements, each class characterizing an electro-facie; (f) correlating the electro-facies with the facies traversed by the borehole; and (g) comparing a recorded log measurement not selected in step (b) to the classes of log measurements to predict the facie of the geological formation traversed by the borehole associated with the level of the log measurement not selected in step (b).
Claim 2
Independent Claim
204 words
A method of predicting the facies of a geological formation traversed by a borehole comprising: (a) moving a sonde through a plurality of predetermined levels in a borehole traversing a geological formation and recording the log measurements taken by the sonde at each of the predetermined levels; (b) selecting the recorded log measurements which are stable over consecutive levels; (c) assigning the selected log measurements to points in an n dimensional space in which n is equal to the number of log measurements recorded at each of the levels; (d) selecting pairs of modes which are furthest apart from each other in the n dimensional space, each of the modes corresponding to a point of maximum density of the points in the n dimensional space; (e) assigning each point in the n dimensional space to the respective closest mode, thereby defining classes of log measurements, each class characterizing an electro-facie; (f) correlating the electro-facies with the facies traversed by the borehole; and (g) comparing a recorded log measurement not selected in step (b) to the classes of log measurements to predict the facie of the geological formation traversed by the borehole associated with the level of the log measurement not selected in step (b).
Claim 3
Dependent Claim
21 words
The method of claim 1 additionally comprising producing a recording of the electro-facies of the geological formation traversed by the borehole.
Claim 4
Dependent Claim
41 words
The method of claim 1 wherein the number of dimensions in the n dimensional space is reduced by limiting n to the number of recorded log measurements representing the maximum variability of the recorded log measurements in the n dimensional space.
Claim 5
Dependent Claim
54 words
The method of claim 3 further comprising defining a line in the n dimensional space for which the distance from each point in the n dimensional space to that line is the smallest and changing the dimensions of the n dimensional space to express the position of that line in the n dimensional space.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein n equals either 1, 2 or 3.
Claim 7
Dependent Claim
45 words
The method of claim 1 wherein the number of dimensions in the n dimensional space is reduced by limiting n to the number of recorded log measurements representing at least about 85% of the variability of the recorded log measurements in the n dimensional space.
Claim 8
Dependent Claim
39 words
The method of claim 1 wherein each point of maximum density of the points in the n dimensional space is selected by determining an index representing the density of the points in the n dimensional space adjoining each point.
Claim 9
Dependent Claim
39 words
The method of claim 7 wherein said index is determined by selecting the hypersphere with the minimum radius, each hypersphere being centered on each point in the n dimensional space and encompassing a predetermined number of nearest neighboring points.
Claim 10
Dependent Claim
17 words
The method of claim 7 wherein the modes are selected by selecting pairs of maximum density indices.
Claim 11
Dependent Claim
39 words
The method of claim 9 wherein the log measurement not selected in step (b) is assigned to a class by testing to determine whether the log measurement not selected in step (b) belongs to a ramp or a bump.
Claim 12
Dependent Claim
53 words
The method of claim 10 wherein said distance is calculated between the point in the n dimensional space corresponding to the log measurement not selected in step (b) and the modes of the classes corresponding to the levels closest in depth to the level of the log measurement not selected in step (b).
Claim 13
Dependent Claim
65 words
The method of claim 10 wherein the determination of whether the log measurement not selected in step (b) belongs to a ramp or a bump comprises selecting a maximum distance above which the log measurement not selected in step (b) is determined to belong to a ramp and below which the log measurement not selected in step (b) is determined to belong to a bump.
Claim 14
Dependent Claim
19 words
The method of claim 1 additionally comprising assigning the log measurement not selected in step (b) to a class.
Claim 15
Dependent Claim
61 words
The method of claim 13 wherein the log measurement not selected in step (b) is tested by calculating the distance between the point in the n dimensional space corresponding to the log measurement not selected in step (b) and the two classes corresponding to the levels closest in depth to the level of the log measurement not selected in step (b).
Claim 16
Dependent Claim
59 words
The method of claim 13 wherein each log measurement belonging to a ramp is assigned to one of the two electro-facies immediately adjacent the level of the ramp in depth, the transition between the two electro-facies being a point equidistant in the n dimensional space from the classes corresponding to the levels of each of the respective adjacent levels.
Claim 17
Dependent Claim
48 words
The method of claim 13 wherein each log measurement belonging to a bump is assigned either to one of the classes defined in step (f) or, if none of the classes defined in step (f) corresponds to the log measurement belonging to a bump, to a different class.
Claim 18
Dependent Claim
12 words
The method of claim 1 wherein the selected log measurements are normalized.
Claim 19
Dependent Claim
39 words
The method of claim 1 wherein the recorded log measurements are selected as being stable over consecutive levels on the basis of whether the recorded log measurements remain within a predetermined range over a predetermined number of consecutive levels.
Claim 20
Dependent Claim
13 words
The method of claim 1 additionally comprising assigning each class an index number.
Claim 21
Dependent Claim
23 words
The method of claim 19 wherein the index number of each class is plotted as a function of the depth of the borehole.
Claim 22
Dependent Claim
19 words
The method of claim 1 wherein the number of pairs of modes selected is limited by a threshold number.
Claim 23
Dependent Claim
22 words
The method of claim 1 additionally comprising correlating the electro-facies from a selected level to the dipmeter data from that selected level.
Claim 24
Independent Claim
245 words
A method of producing a recording characteristic of the facies of a geological formation traversed by a borehole comprising: (a) moving a sonde through a plurality of predetermined levels in a borehole traversing a geological formation and recording the log measurements taken by the sonde at each of the predetermined levels; (b) selecting recorded log measurements which remain within a predetermined range over a predetermined number of consecutive levels; (c) normalizing the selected log measurements; (d) assigning the selected log measurements to points in an n dimensional space, n being limited to the number of recorded log measurements representing about 85% of the variability of the recorded log measurements in the n dimensional space; (e) selecting pairs of modes which are furthest apart from each other in the n dimensional space, each of the modes corresponding to a point of maximum density of the points in the n dimensional space; (f) assigning each point in the n dimensional space to the respective closest mode to define classes of log measurements, each class characerizing an electro-facies; (g) correlating the electro-facies with the facies traversed by the borehole; (h) comparing a recorded log measurement not selected in step (b) to the classes of log measurements to predict the facie of the geological formation traversed by the borehole associated with the level of the log measurement not selected in step (b); and (i) producing a recording of the electro-facies as a function of the depth of the borehole.
Claim 25
Independent Claim
245 words
A method of producing a recording characteristic of the facies of a geological formation traversed by a borehole comprising: (a) moving a sonde through a plurality of predetermined levels in a borehole traversing a geological formation and recording the log measurements taken by the sonde at each of the predetermined levels; (b) selecting recorded log measurements which remain within a predetermined range over a predetermined number of consecutive levels; (c) normalizing the selected log measurements; (d) assigning the selected log measurements to points in an n dimensional space, n being limited to the number of recorded log measurements representing about 85% of the variability of the recorded log measurements in the n dimensional space; (e) selecting pairs of modes which are furthest apart from each other in the n dimensional space, each of the modes corresponding to a point of maximum density of the points in the n dimensional space; (f) assigning each point in the n dimensional space to the respective closest mode to define classes of log measurements, each class characerizing an electro-facies; (g) correlating the electro-facies with the facies traversed by the borehole; (h) comparing a recorded log measurement not selected in step (b) to the classes of log measurements to predict the facie of the geological formation traversed by the borehole associated with the level of the log measurement not selected in step (b); and (i) producing a recording of the electro-facies as a function of the depth of the borehole.
Claim 26
Dependent Claim
227 words
Apparatus for producing a recording representing the facies of a geological formation traversed by a borehole comprising: means movable through a borehole for producing log measurements from a plurality of predetermined levels of the borehole; means for selecting the log measurements produced by said log measurement producing means which are stable over consecutive levels traversed by said log measurement producing means; means for normalizing the log measurements produced by said log measurement producing means; means for assigning the log measurements produced by said log measurement producing means to points in an n dimensional space in which n is equal to the number of log measurements recorded at each of the levels; means for selecting pairs of modes which are furthest apart from each other in the n dimensional space, each of the modes corresponding to a point of maximum density of the points in the n dimensional space; means for defining classes of log measurements by assigning each point in the n dimensional space to the respective closest mode selected by said mode selecting means, each of the classes characterizing an electro-facies; means for correlating the electro-facies with the facies of the geological formation traversed by said log measurement producing means; and means for producing a recording representing the correlation of the facies of the geological formation traversed by said log measurement producing means to the electro-facies.
Claim 27
Dependent Claim
227 words
Apparatus for producing a recording representing the facies of a geological formation traversed by a borehole comprising: means movable through a borehole for producing log measurements from a plurality of predetermined levels of the borehole; means for selecting the log measurements produced by said log measurement producing means which are stable over consecutive levels traversed by said log measurement producing means; means for normalizing the log measurements produced by said log measurement producing means; means for assigning the log measurements produced by said log measurement producing means to points in an n dimensional space in which n is equal to the number of log measurements recorded at each of the levels; means for selecting pairs of modes which are furthest apart from each other in the n dimensional space, each of the modes corresponding to a point of maximum density of the points in the n dimensional space; means for defining classes of log measurements by assigning each point in the n dimensional space to the respective closest mode selected by said mode selecting means, each of the classes characterizing an electro-facies; means for correlating the electro-facies with the facies of the geological formation traversed by said log measurement producing means; and means for producing a recording representing the correlation of the facies of the geological formation traversed by said log measurement producing means to the electro-facies.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |